Related to the Alex post I think it is incorrect to define the domain name in a service docker container for the application or in the UNA app server. the application must run in localhost or any ip address and any port depend of the setup, the domain must be defined only in the reverse proxy server or a web server level, so you can run multiple containers with the app in a swarm or a cluster with more many containers or on several servers in bachend, each service can be scalable and extended in the cloud without problems. Otherwise, a social network cannot be built in a single server, this is just an illusion